1. Field of the Invention
This disclosure relates in general to an improved maneuvering system for small boats, and more particularly to a bow thruster for small boats which greatly facilitates operations done at slow speeds such as docking in congested area.
2. Discussion of the Prior Art
The increased congestion present in many docking areas for small boats has created a problem for the boat operators. Small boats are usually maneuvered by the propulsion system located in the rear of the boat. Either a steerable outboard engine or rudder pivoted to one direction or the other with a consequent movement of the bow of the boat to the opposite side. In small, cramped spaces maneuvering the boat is difficult at best even for many skilled operators, and many accidents such as ramming another vessel or the dock occur. The problem of maneuverability exists because the bow of the boat responds only to the engine or rudder in the rear. The present invention provides an auxiliary maneuvering system which enables the operator to steer the bow of the boat as well as the stern, making the boat much more maneuverable. In the past, apparatus for steering the bow of a small boat that the applicant has been have had many limitations. Such steering devices include those requiring the cutting of large holes through the bow of the boat to install a large propeller in a tube transverse to the bow of the vessel. Such units have difficult hull installation and require substantial hull repair after installation. Further, the large transverse tunnel with the propeller enclosed creates a water trap which in turn increases the flow drag on the boat hull, making the vessel more difficult to propel through the water. The speed of the boat, therefore, is lowered and fuel consumption increased. The present invention uses only small diameter inlet and outlet fittings through the hull and therefore avoids many of the above-mentioned problems.
A preliminary search of the prior art was performed by applicant and the following patents were found to be of possible interest:
______________________________________ U.S. Pat. No. ISSUE DATE INVENTOR ______________________________________ 917,201 4/6/09 Vollmer 961,306 6/14/10 Mayell 1,240,932 9/25/17 Brown et al 3,078,661 2/26/63 Spence 4,056,973 11/1/77 Dashew et al 4,214,544 7/29/80 Dashew et al 4,265,192 5/5/81 Dunn ______________________________________
In the patents discovered by the search, the first three, namely Vollmer, Mayall, and Brown et al, have various propelling and steering apparatus which discharge water below the water line of the boat which is not what applicant does, and in fact, would not work for his application. Spence shows nozzles which discharge to the rear of the boat unlike applicant's apparatus although they do discharge above the water line. The two Dashew et al patents and the Dunn patent show discharge of water above the water line in the bow of the boat as does applicant. The present invention, however, differs significantly from these inventions which require control valves and a relatively complicated arrangement of conduits to perform. Applicant's invention does not require control valves, and does not require a bypass conduit such as Dunn requires while the water pump is operating, but before maneuvering is to occur. Applicant's system is controlled simply by an activation switch which can turn the water pump on in a normal or reversed mode or turn the pump off. The direction of bow thrust is controlled by this switch. The present invention has the advantage of being simple, easier to install and less expensive than the system of Dunn or Dashew et al.
It should be noted that a further possible reference is Dornak (U.S. Pat. No. 3,933,113). Dornak's apparatus functions in a different manner than applicant's apparatus. The rotation of Dornak's apparatus is rotation of his nozzle 23, not his pump. The nozzle 23 could be rotated to a different discharge position. The present invention does not rotate any nozzle or the direction of nozzle discharge. If Dornak's pump 32 were reversed, the flow of water would be from the nozzle 23 to an exit in the bottom of the hull producing no directional change as the present invention can by a reversal of pump rotational direction. In other words, reversing Dornak's pump would make his entire system inoperable. Further, it would not be obvious given Dornak how to reverse his pump and produce directional change successfully as does the present invention due to the difference in function and structure of his apparatus vis-a-vis the present invention. Further, the present invention claims at least two rotors in addition to the above arguments which distinguish the present invention from Dornak.
Further comments can be made regarding Dashew et al (U.S. Pat. No. 4,056,073) which was cited in the parent case. Firstly, valve 44 is a directional control valve used by Dashew et al. applicant's desire from a functional and economic standpoint was to use a simple apparatus to achieve maneuvering in tight spaces without using a valve as does Dashew et al. The present invention has no directional valves, nor would desire any valves due to complexity and economic considerations. The two rotors of the pump of the present invention in a unique way, given the prior art, perform the directional changes required, taking the place of a valve 44 as shown in Dashew et al. The use of the pump with its rotors as in the present invention would not be obvious given Dashew et al who shows only a valve to change direction. The valve may obtain a result of maneuvering the boat, but is different structurally vis-a-vis the present application. This structural difference is a key difference and in this difference lies the heart of the present invention. Further, Dashew et al does not go as far as to render the present invention obvious. The valve 44 is too much different than the use of two rotors in a pump to achieve directional control. The present invention can eliminate the use of directional valving with its apparatus. This factor should show that this invention differs enough from Dashew et al as to render it patentable over Dashew et al.